drivers/input/keyboard/nspire-keypad.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au>
   4  */
   5
   6 #include <linux/input/matrix_keypad.h>
   7 #include <linux/platform_device.h>
   8 #include <linux/interrupt.h>
   9 #include <linux/io.h>
  10 #include <linux/delay.h>
  11 #include <linux/input.h>
  12 #include <linux/slab.h>
  13 #include <linux/clk.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16
  17 #define KEYPAD_SCAN_MODE        0x00
  18 #define KEYPAD_CNTL             0x04
  19 #define KEYPAD_INT              0x08
  20 #define KEYPAD_INTMSK           0x0C
  21
  22 #define KEYPAD_DATA             0x10
  23 #define KEYPAD_GPIO             0x30
  24
  25 #define KEYPAD_UNKNOWN_INT      0x40
  26 #define KEYPAD_UNKNOWN_INT_STS  0x44
  27
  28 #define KEYPAD_BITMASK_COLS     11
  29 #define KEYPAD_BITMASK_ROWS     8
  30
  31 struct nspire_keypad {
  32         void __iomem *reg_base;
  33         u32 int_mask;
  34
  35         struct input_dev *input;
  36         struct clk *clk;
  37
  38         struct matrix_keymap_data *keymap;
  39         int row_shift;
  40
  41         /* Maximum delay estimated assuming 33MHz APB */
  42         u32 scan_interval;      /* In microseconds (~2000us max) */
  43         u32 row_delay;          /* In microseconds (~500us max) */
  44
  45         u16 state[KEYPAD_BITMASK_ROWS];
  46
  47         bool active_low;
  48 };
  49
  50 static irqreturn_t nspire_keypad_irq(int irq, void *dev_id)
  51 {
  52         struct nspire_keypad *keypad = dev_id;
  53         struct input_dev *input = keypad->input;
  54         unsigned short *keymap = input->keycode;
  55         unsigned int code;
  56         int row, col;
  57         u32 int_sts;
  58         u16 state[8];
  59         u16 bits, changed;
  60
  61         int_sts = readl(keypad->reg_base + KEYPAD_INT) & keypad->int_mask;
  62         if (!int_sts)
  63                 return IRQ_NONE;
  64
  65         memcpy_fromio(state, keypad->reg_base + KEYPAD_DATA, sizeof(state));
  66
  67         for (row = 0; row < KEYPAD_BITMASK_ROWS; row++) {
  68                 bits = state[row];
  69                 if (keypad->active_low)
  70                         bits = ~bits;
  71
  72                 changed = bits ^ keypad->state[row];
  73                 if (!changed)
  74                         continue;
  75
  76                 keypad->state[row] = bits;
  77
  78                 for (col = 0; col < KEYPAD_BITMASK_COLS; col++) {
  79                         if (!(changed & (1U << col)))
  80                                 continue;
  81
  82                         code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
  83                         input_event(input, EV_MSC, MSC_SCAN, code);
  84                         input_report_key(input, keymap[code],
  85                                          bits & (1U << col));
  86                 }
  87         }
  88
  89         input_sync(input);
  90
  91         writel(0x3, keypad->reg_base + KEYPAD_INT);
  92
  93         return IRQ_HANDLED;
  94 }
  95
  96 static int nspire_keypad_open(struct input_dev *input)
  97 {
  98         struct nspire_keypad *keypad = input_get_drvdata(input);
  99         unsigned long val = 0, cycles_per_us, delay_cycles, row_delay_cycles;
 100         int error;
 101
 102         error = clk_prepare_enable(keypad->clk);
 103         if (error)
 104                 return error;
 105
 106         cycles_per_us = (clk_get_rate(keypad->clk) / 1000000);
 107         if (cycles_per_us == 0)
 108                 cycles_per_us = 1;
 109
 110         delay_cycles = cycles_per_us * keypad->scan_interval;
 111         WARN_ON(delay_cycles >= (1 << 16)); /* Overflow */
 112         delay_cycles &= 0xffff;
 113
 114         row_delay_cycles = cycles_per_us * keypad->row_delay;
 115         WARN_ON(row_delay_cycles >= (1 << 14)); /* Overflow */
 116         row_delay_cycles &= 0x3fff;
 117
 118         val |= 3 << 0; /* Set scan mode to 3 (continuous scan) */
 119         val |= row_delay_cycles << 2; /* Delay between scanning each row */
 120         val |= delay_cycles << 16; /* Delay between scans */
 121         writel(val, keypad->reg_base + KEYPAD_SCAN_MODE);
 122
 123         val = (KEYPAD_BITMASK_ROWS & 0xff) | (KEYPAD_BITMASK_COLS & 0xff)<<8;
 124         writel(val, keypad->reg_base + KEYPAD_CNTL);
 125
 126         /* Enable interrupts */
 127         keypad->int_mask = 1 << 1;
 128         writel(keypad->int_mask, keypad->reg_base + KEYPAD_INTMSK);
 129
 130         return 0;
 131 }
 132
 133 static void nspire_keypad_close(struct input_dev *input)
 134 {
 135         struct nspire_keypad *keypad = input_get_drvdata(input);
 136
 137         /* Disable interrupts */
 138         writel(0, keypad->reg_base + KEYPAD_INTMSK);
 139         /* Acknowledge existing interrupts */
 140         writel(~0, keypad->reg_base + KEYPAD_INT);
 141
 142         clk_disable_unprepare(keypad->clk);
 143 }
 144
 145 static int nspire_keypad_probe(struct platform_device *pdev)
 146 {
 147         const struct device_node *of_node = pdev->dev.of_node;
 148         struct nspire_keypad *keypad;
 149         struct input_dev *input;
 150         struct resource *res;
 151         int irq;
 152         int error;
 153
 154         irq = platform_get_irq(pdev, 0);
 155         if (irq < 0)
 156                 return -EINVAL;
 157
 158         keypad = devm_kzalloc(&pdev->dev, sizeof(struct nspire_keypad),
 159                               GFP_KERNEL);
 160         if (!keypad) {
 161                 dev_err(&pdev->dev, "failed to allocate keypad memory\n");
 162                 return -ENOMEM;
 163         }
 164
 165         keypad->row_shift = get_count_order(KEYPAD_BITMASK_COLS);
 166
 167         error = of_property_read_u32(of_node, "scan-interval",
 168                                      &keypad->scan_interval);
 169         if (error) {
 170                 dev_err(&pdev->dev, "failed to get scan-interval\n");
 171                 return error;
 172         }
 173
 174         error = of_property_read_u32(of_node, "row-delay",
 175                                      &keypad->row_delay);
 176         if (error) {
 177                 dev_err(&pdev->dev, "failed to get row-delay\n");
 178                 return error;
 179         }
 180
 181         keypad->active_low = of_property_read_bool(of_node, "active-low");
 182
 183         keypad->clk = devm_clk_get(&pdev->dev, NULL);
 184         if (IS_ERR(keypad->clk)) {
 185                 dev_err(&pdev->dev, "unable to get clock\n");
 186                 return PTR_ERR(keypad->clk);
 187         }
 188
 189         keypad->reg_base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
 190         if (IS_ERR(keypad->reg_base))
 191                 return PTR_ERR(keypad->reg_base);
 192
 193         keypad->input = input = devm_input_allocate_device(&pdev->dev);
 194         if (!input) {
 195                 dev_err(&pdev->dev, "failed to allocate input device\n");
 196                 return -ENOMEM;
 197         }
 198
 199         error = clk_prepare_enable(keypad->clk);
 200         if (error) {
 201                 dev_err(&pdev->dev, "failed to enable clock\n");
 202                 return error;
 203         }
 204
 205         /* Disable interrupts */
 206         writel(0, keypad->reg_base + KEYPAD_INTMSK);
 207         /* Acknowledge existing interrupts */
 208         writel(~0, keypad->reg_base + KEYPAD_INT);
 209
 210         /* Disable GPIO interrupts to prevent hanging on touchpad */
 211         /* Possibly used to detect touchpad events */
 212         writel(0, keypad->reg_base + KEYPAD_UNKNOWN_INT);
 213         /* Acknowledge existing GPIO interrupts */
 214         writel(~0, keypad->reg_base + KEYPAD_UNKNOWN_INT_STS);
 215
 216         clk_disable_unprepare(keypad->clk);
 217
 218         input_set_drvdata(input, keypad);
 219
 220         input->id.bustype = BUS_HOST;
 221         input->name = "nspire-keypad";
 222         input->open = nspire_keypad_open;
 223         input->close = nspire_keypad_close;
 224
 225         __set_bit(EV_KEY, input->evbit);
 226         __set_bit(EV_REP, input->evbit);
 227         input_set_capability(input, EV_MSC, MSC_SCAN);
 228
 229         error = matrix_keypad_build_keymap(NULL, NULL,
 230                                            KEYPAD_BITMASK_ROWS,
 231                                            KEYPAD_BITMASK_COLS,
 232                                            NULL, input);
 233         if (error) {
 234                 dev_err(&pdev->dev, "building keymap failed\n");
 235                 return error;
 236         }
 237
 238         error = devm_request_irq(&pdev->dev, irq, nspire_keypad_irq, 0,
 239                                  "nspire_keypad", keypad);
 240         if (error) {
 241                 dev_err(&pdev->dev, "allocate irq %d failed\n", irq);
 242                 return error;
 243         }
 244
 245         error = input_register_device(input);
 246         if (error) {
 247                 dev_err(&pdev->dev,
 248                         "unable to register input device: %d\n", error);
 249                 return error;
 250         }
 251
 252         dev_dbg(&pdev->dev,
 253                 "TI-NSPIRE keypad at %pR (scan_interval=%uus, row_delay=%uus%s)\n",
 254                 res, keypad->row_delay, keypad->scan_interval,
 255                 keypad->active_low ? ", active_low" : "");
 256
 257         return 0;
 258 }
 259
 260 static const struct of_device_id nspire_keypad_dt_match[] = {
 261         { .compatible = "ti,nspire-keypad" },
 262         { },
 263 };
 264 MODULE_DEVICE_TABLE(of, nspire_keypad_dt_match);
 265
 266 static struct platform_driver nspire_keypad_driver = {
 267         .driver = {
 268                 .name = "nspire-keypad",
 269                 .of_match_table = nspire_keypad_dt_match,
 270         },
 271         .probe = nspire_keypad_probe,
 272 };
 273
 274 module_platform_driver(nspire_keypad_driver);
 275
 276 MODULE_LICENSE("GPL");
 277 MODULE_DESCRIPTION("TI-NSPIRE Keypad Driver");